Properties of mortars incorporating rice husk ash and burnt shells | |
| Author | Watanapong Hiranmarn |
| Call Number | AIT Thesis no.ST-00-29 |
| Subject(s) | Mortar--Additives Rice hull ash |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The properties of burnt shell-rice husk ash (RHA) were investigated to consider its possible use as a cementitious material. The aim is to enable villagers of developing countries especially along the coastal areas or archipelagoes where hydraulic cement is not available to make their own cementitious materials. A ferrocement incinerator and the grinding machine· developed earlier at the Asian Institute of Technology were used for burning and grinding of RHA. Three types of shell, namely cockleshell, green mussel shell and oyster shell were used and burnt in electric furnace at 950 °C for 5 hours to obtain lime. Two main parts of tests were conducted and these are referred to as Part I and Part II. In Part I, the determination of optimum type of shell and proportion of burnt shell-RHA was investigated. Part II was set up to improve the compressive strength of burnt shell-RHA mortar by using aluminium oxide and gypsum as additives. The mechanical properties which were investigated include setting times, change in height at early ages, length change of hardened mortars and compressive strengths at different ages. In addition, its resistance against acid attack was also tested. The test results indicated that among the three types of shell investigated, oyster shell which can be produced by burning at 950 °C for 5 hours is found to be the most reactive when interground with RHA whereas, cockleshell is found to be the least reactive when interground with RHA. The optimum ratio of oyster shell to RHA to produce the highest compressive strength of oyster shell-RHA mortar having the same workability is found to be 1: 1 by weight. For both green mussel shell and cockleshell, the optimum ratio to produce optimum compressive strength is 1 :2. The 28 days compressive strength of mortars containing all types of shell and RHA were found to satisfy the minimum strength requirement according ASTM C91. The optimum dosage of aluminium oxide and gypsum to improve the compressive strength of mortar are 1.5 and 5.0 percent by weight of cementitious material respectively. Gypsum shows higher strength than aluminium oxide. However, simultaneous use of aluminium oxide and gypsum gives lower compressive strength than that of aluminium oxide alone or gypsum alone. The results from acid attack tests indicated that the resistance against sulfuric acid of oyster-RHA mortar is significantly higher than that of OPC mortar. On the other hand, green mussel shell-RHA mortar showed poor resistance against sulfuric acid attack. |
| Year | 2000 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul; |
| Examination Committee(s) | Nii, Kazuyoshi ;Pennung Warnitchai; |
| Scholarship Donor(s) | Mahanakorn University of Technology; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2000 |